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transcranial ultrasound

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https://www.readbyqxmd.com/read/27881556/nitrite-and-s-nitrosohemoglobin-exchange-across-the-human-cerebral-and-femoral-circulation-relationship-to-basal-and-exercise-blood-flow-responses-to-hypoxia
#1
Damian M Bailey, Peter Rasmussen, Morten Overgaard, Kevin A Evans, Aske M Bohm, Thomas Seifert, Patrice Brassard, Morten Zaar, Henning B Nielsen, Peter Raven, Niels H Secher
BACKGROUND: -The mechanisms underlying red blood cell (RBC)-mediated hypoxic vasodilation remain controversial with separate roles for nitrite (NO2(-)) and S-nitrosohemoglobin (SNO-Hb) widely contested given their ability to transduce nitric oxide (NO) bioactivity within the microcirculation. To establish their relative contribution in vivo, we quantified arterial-venous (a-v) concentration gradients across the human cerebral and femoral circulation at rest and during exercise, an ideal model system characterized by physiological extremes of O2 tension and blood flow...
November 15, 2016: Circulation
https://www.readbyqxmd.com/read/27875362/relationship-between-hiv-infection-antiretroviral-therapy-inflammatory-markers-and-cerebrovascular-endothelial-function-among-adults-in-urban-china
#2
Felicia C Chow, Yanling Li, Yinghuan Hu, Joy Chan, Huanling Wang, Weihai Xu, Richard W Price, Farzaneh A Sorond, Taisheng Li
BACKGROUND: Cerebrovascular risk is increased in people living with HIV infection compared with age-matched uninfected individuals. Cerebrovascular endothelial dysfunction related to antiretroviral therapy and inflammation may contribute to higher stroke risk in HIV infection. METHODS: We compared cerebral vasoreactivity-a measure of cerebrovascular endothelial function assessed by the breath holding index (BHI) using transcranial Doppler ultrasound-between virologically suppressed Chinese HIV-infected individuals followed in an HIV clinic in Beijing, China and uninfected controls...
November 21, 2016: Journal of Acquired Immune Deficiency Syndromes: JAIDS
https://www.readbyqxmd.com/read/27845920/a-multi-frequency-sparse-hemispherical-ultrasound-phased-array-for-microbubble-mediated-transcranial-therapy-and-simultaneous-cavitation-mapping
#3
Lulu Deng, Meaghan A O'Reilly, Ryan M Jones, Ran An, Kullervo Hynynen
Focused ultrasound (FUS) phased arrays show promise for non-invasive brain therapy. However, the majority of them are limited to a single transmit/receive frequency and therefore lack the versatility to expose and monitor the treatment volume. Multi-frequency arrays could offer variable transmit focal sizes under a fixed aperture, and detect different spectral content on receive for imaging purposes. Here, a three-frequency (306, 612, and 1224 kHz) sparse hemispherical ultrasound phased array (31.8 cm aperture; 128 transducer modules) was constructed and evaluated for microbubble-mediated transcranial therapy and simultaneous cavitation mapping...
December 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27843693/treatment-and-imaging-of-intracranial-atherosclerotic-stenosis-current-perspectives-and-future-directions
#4
REVIEW
Ido R van den Wijngaard, Ghislaine Holswilder, Marianne A A van Walderveen, Ale Algra, Marieke J H Wermer, Osama O Zaidat, Jelis Boiten
BACKGROUND AND PURPOSE: Intracranial atherosclerosis is a common cause of stroke worldwide. It results in ischemic stroke due to different mechanisms including artery-to-artery embolism, in situ thrombo-occlusion, occlusion of perforating arteries, and hemodynamic failure. In this review, we present an overview of current treatment and imaging modalities in intracranial atherosclerotic stenosis. METHODS: PubMed was searched for relevant articles in English that evaluated the treatment and imaging of intracranial atherosclerotic stenosis (ICAS)...
November 2016: Brain and Behavior
https://www.readbyqxmd.com/read/27837190/hyperoxia-results-in-increased-aerobic-metabolism-following-acute-brain-injury
#5
Arnab Ghosh, David Highton, Christina Kolyva, Ilias Tachtsidis, Clare E Elwell, Martin Smith
Acute brain injury is associated with depressed aerobic metabolism. Below a critical mitochondrial pO2 cytochrome c oxidase, the terminal electron acceptor in the mitochondrial respiratory chain, fails to sustain oxidative phosphorylation. After acute brain injury, this ischaemic threshold might be shifted into apparently normal levels of tissue oxygenation. We investigated the oxygen dependency of aerobic metabolism in 16 acutely brain-injured patients using a 120-min normobaric hyperoxia challenge in the acute phase (24-72 h) post-injury and multimodal neuromonitoring, including transcranial Doppler ultrasound-measured cerebral blood flow velocity, cerebral microdialysis-derived lactate-pyruvate ratio (LPR), brain tissue pO2 (pbrO2), and tissue oxygenation index and cytochrome c oxidase oxidation state (oxCCO) measured using broadband spectroscopy...
November 11, 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27796172/risk-factors-between-intracranial-extracranial-atherosclerosis-and-anterior-posterior-circulation-stroke-in-ischaemic-stroke
#6
Yan Li, Yefeng Cai, Min Zhao, Jingbo Sun
OBJECTIVES: Atherosclerosis is an important cause of stroke and remains a challenge for stroke prevention. Risk factors involved in atherosclerotic stroke and anterior and posterior circulation strokes (ACS and PCS, respectively) are different. The purpose of this study is to investigate differences in risk factors between intracranial and extracranial atherosclerosis (ICAS and ECAS), ACS and PCS, and ICAS/ECAS with ACS/PCS in a Chinese acute ischaemic stroke population. METHODS: We analysed 551 ischaemic stroke patients who had been enrolled between August 2005 and July 2008...
October 31, 2016: Neurological Research
https://www.readbyqxmd.com/read/27786169/therapeutic-potential-of-transcranial-focused-ultrasound-for-rett-syndrome
#7
Shih-Jen Tsai
Rett syndrome (RTT) is a severe neurodevelopmental disorder occurring almost exclusively in females and is caused by loss-of-function mutations in the gene encoding methyl-CpG-binding protein 2 (MeCP2) in the majority of cases. MeCP2 is essential for the normal function of nerve cells, including neuronal development, maturation, and synaptic activity. RTT is characterized by normal early development followed by autistic-like features, slowed brain and head growth, gait abnormalities, seizures, breathing irregularities, and cognitive disabilities...
October 27, 2016: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/27784293/simultaneous-acoustic-stimulation-of-human-primary-and-secondary-somatosensory-cortices-using-transcranial-focused-ultrasound
#8
Wonhye Lee, Yong An Chung, Yujin Jung, In-Uk Song, Seung-Schik Yoo
BACKGROUND: Transcranial focused ultrasound (FUS) is gaining momentum as a novel non-invasive brain stimulation method, with promising potential for superior spatial resolution and depth penetration compared to transcranial magnetic stimulation or transcranial direct current stimulation. We examined the presence of tactile sensations elicited by FUS stimulation of two separate brain regions in humans-the primary (SI) and secondary (SII) somatosensory areas of the hand, as guided by individual-specific functional magnetic resonance imaging data...
October 26, 2016: BMC Neuroscience
https://www.readbyqxmd.com/read/27779134/a-numerical-study-on-the-oblique-focus-in-mr-guided-transcranial-focused-ultrasound
#9
Alec Hughes, Yuexi Huang, Aki Pulkkinen, Michael L Schwartz, Andres M Lozano, Kullervo Hynynen
Recent clinical data showing thermal lesions from treatments of essential tremor using MR-guided transcranial focused ultrasound shows that in many cases the focus is oblique to the main axis of the phased array. The potential for this obliquity to extend the focus into lateral regions of the brain has led to speculation as to the cause of the oblique focus, and whether it is possible to realign the focus. Numerical simulations were performed on clinical export data to analyze the causes of the oblique focus and determine methods for its correction...
November 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27757739/cerebral-hemodynamics-in-sepsis-assessed-by-transcranial-doppler-a-systematic-review-and-meta-analysis
#10
Daniel Silva de Azevedo, Angela Salomao Macedo Salinet, Marcelo de Lima Oliveira, Manoel Jacobsen Teixeira, Edson Bor-Seng-Shu, Ricardo de Carvalho Nogueira
Cerebral microcirculation is gradually compromised during sepsis, with significant reductions in the function of capillaries and blood perfusion in small vessels. Transcranial Doppler ultrasound (TCD) has been used to assess cerebral circulation in a typical clinical setting. This study was to systematically review TCD studies, assess their methodological quality, and identify trends that can be associated with the temporal evolution of sepsis and its clinical outcome. A meta-analysis of systematic reviews was conducted according to the PRISMA statement...
October 18, 2016: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/27754235/os-34-02-concentration-dependent-effect-of-plasma-resveratrol-on-cerebral-vasodilator-responsiveness-cvr-in-adults-with-type-2-diabetes-mellitus-t2dm
#11
Rachel Wong, Rhenan Nealon, Daniel Raederstorff, Peter Howe
OBJECTIVE: Having shown that resveratrol consumption can improve flow mediated dilation of the brachial artery, we tested its effects on CVR to hypercapnia in adults with T2DM, a risk population for cerebrovascular disease and cognitive impairments. DESIGN AND METHOD: In a double-blind crossover trial, 34 adults with T2DM consumed 0, 75, 150 and 300 mg of synthetic trans-resveratrol (one dose per week in random order). Before and 1-2 hr after dosing, transcranial Doppler ultrasound was used to assess CVR to a hypercapnic stimulus (breathing Carbogen gas for 3 min) in the middle (MCA) and posterior (PCA) cerebral arteries...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27740993/ultrasound-in-neurology
#12
Georgios Tsivgoulis, Andrei V Alexandrov
PURPOSE OF REVIEW: Low cost, avoidance of irradiation, and high temporal resolution are inherent advantages of ultrasound imaging that translate into multiple clinical uses in many domains of neurology. This article presents clinical uses of ultrasound examination in cerebrovascular, neurodegenerative, and peripheral nervous system diseases. RECENT FINDINGS: Modern treatment and prevention of ischemic stroke rely on prompt diagnosis. Ultrasonography has found a place as a noninvasive screening test and bedside technique that provides estimates of the degree of stenosis as well as hemodynamic and structural information about intracranial and extracranial vessels in real time...
October 2016: Continuum: Lifelong Learning in Neurology
https://www.readbyqxmd.com/read/27740941/preclinical-evaluation-of-a-low-frequency-transcranial-mri-guided-focused-ultrasound-system-in-a-primate-model
#13
Nathan McDannold, Margaret Livingstone, Can Barış Top, Jonathan Sutton, Nick Todd, Natalia Vykhodtseva
This study investigated thermal ablation and skull-induced heating with a 230 kHz transcranial MRI-guided focused ultrasound (TcMRgFUS) system in nonhuman primates. We evaluated real-time acoustic feedback and aimed to understand whether cavitation contributed to the heating and the lesion formation. In four macaques, we sonicated thalamic targets at acoustic powers of 34-560 W (896-7590 J). Tissue effects evaluated with MRI and histology were compared to MRI-based temperature and thermal dose measurements, acoustic emissions recorded during the experiments, and acoustic and thermal simulations...
November 7, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27721780/the-need-for-a-rational-approach-to-vasoconstrictive-syndromes-transcranial-doppler-and-calcium-channel-blockade-in-reversible-cerebral-vasoconstriction-syndrome
#14
Elisabeth B Marsh, Wendy C Ziai, Rafael H Llinas
INTRODUCTION: Reversible cerebral vasoconstriction syndrome (RCVS) typically affects young patients and left untreated can result in hemorrhage or ischemic stroke. Though the disorder has been well characterized in the literature, the most appropriate way to diagnose, treat, and evaluate therapeutic response remains unclear. In previous studies, transcranial Doppler ultrasound (TCD) has shown elevated velocities indicative of vasospasm. This imaging modality is noninvasive and inexpensive; an attractive option for diagnosis and therapeutic monitoring if it is sensitive enough to detect changes in the acute setting given that RCVS often affects the distal vessels early in the course of disease...
May 2016: Case Reports in Neurology
https://www.readbyqxmd.com/read/27699844/specialized-volumetric-thermometry-for-improved-guidance-of-mrgfus-in-brain
#15
Michael Marx, Pejman Ghanouni, Kim Butts Pauly
PURPOSE: MR thermometry is critical for safe and effective transcranial focused ultrasound. The current single-slice MR thermometry sequence cannot achieve all desired treatment monitoring requirements. We propose an approach in which the imaging requirements of different aspects of treatment monitoring are met by optimizing multiple sequences. METHODS: Imaging requirements were determined for three stages of MR-guided focused ultrasound brain treatment: 1) focal spot localization, 2) focal spot monitoring, and 3) background monitoring...
October 4, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27692991/-chronic-brain-damage-in-sickle-cell-disease-and-its-relation-with-quality-of-life
#16
Elena Cela, Ana G Vélez, Alejandra Aguado, Gabriela Medín, José M Bellón, Cristina Beléndez
BACKGROUND AND OBJECTIVE: Sickle cell anaemia causes progressive organ damage. The objective is to describe school performance of patients with sickle cell anaemia and their clinical parameters and quality of life that may have an influence. The hypothesis is that if school alterations occur without other objective data, additional factors must be present besides the disease itself. PATIENTS AND METHODS: Transversal study performed in November 2015 considering analytical variables, complications and neuroradiological images of children with sickle cell anaemia, and family survey on school performance and quality of life...
September 29, 2016: Medicina Clínica
https://www.readbyqxmd.com/read/27689154/the-posterior-cerebral-artery-and-its-main-cortical-branches-identified-with-noninvasive-transcranial-color-coded-duplex-sonography
#17
P E Frid, S J Schreiber, O Pade, F Doepp, J Valdueza
PURPOSE: To differentiate PCA segments and cortical branches by means of transcranial color-coded duplex sonography (TCCD) and to measure flow parameters at rest and during visual stimulation. MATERIALS AND METHODS: 60 healthy subjects with a good acoustic temporal bone window were examined. The main stem of the PCA (P1, P2 and P3) and 4 main cortical branches - the anterior temporal artery (ATA), the occipital temporal artery (OTA), the parietooccipital artery (POA) and the calcarine artery (CA) - were assessed using an axial transtemporal approach...
November 2015: Ultrasound International Open
https://www.readbyqxmd.com/read/27658372/transcranial-focused-ultrasound-stimulation-of-human-primary-visual-cortex
#18
Wonhye Lee, Hyun-Chul Kim, Yujin Jung, Yong An Chung, In-Uk Song, Jong-Hwan Lee, Seung-Schik Yoo
Transcranial focused ultrasound (FUS) is making progress as a new non-invasive mode of regional brain stimulation. Current evidence of FUS-mediated neurostimulation for humans has been limited to the observation of subjective sensory manifestations and electrophysiological responses, thus warranting the identification of stimulated brain regions. Here, we report FUS sonication of the primary visual cortex (V1) in humans, resulting in elicited activation not only from the sonicated brain area, but also from the network of regions involved in visual and higher-order cognitive processes (as revealed by simultaneous acquisition of blood-oxygenation-level-dependent functional magnetic resonance imaging)...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27643195/os-34-02-concentration-dependent-effect-of-plasma-resveratrol-on-cerebral-vasodilator-responsiveness-cvr-in-adults-with-type-2-diabetes-mellitus-t2dm
#19
Rachel Wong, Rhenan Nealon, Daniel Raederstorff, Peter Howe
OBJECTIVE: Having shown that resveratrol consumption can improve flow mediated dilation of the brachial artery, we tested its effects on CVR to hypercapnia in adults with T2DM, a risk population for cerebrovascular disease and cognitive impairments. DESIGN AND METHOD: In a double-blind crossover trial, 34 adults with T2DM consumed 0, 75, 150 and 300 mg of synthetic trans-resveratrol (one dose per week in random order). Before and 1-2 hr after dosing, transcranial Doppler ultrasound was used to assess CVR to a hypercapnic stimulus (breathing Carbogen gas for 3 min) in the middle (MCA) and posterior (PCA) cerebral arteries...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27642106/transcranial-sonography-of-subcortical-structures-in-patients-with-multiple-sclerosis
#20
P Puz, A Lasek-Bal, P Radecka
BACKGROUND: Transcranial sonography may be applied to assess the basal ganglia nuclei and brain atrophy by the measurement of the width of the third ventricle. The aim of this study was to assess usefulness of transcranial sonography (TCS) in patients with multiple sclerosis (MS) by examining the echogenicity of subcortical structures and the width of the third ventricle. METHOD: Transcranial sonography evaluation of substantia nigra, brain stem raphe nuclei, diameter of the third ventricle, width of the anterior horn of the lateral ventricle, thalamus, lenticular nucleus, and head of the caudate nucleus in 41 patients with relapsing-remitting MS (RRMS), 23 with secondary progressive MS (SPMS), and 20 healthy controls was compared...
September 18, 2016: Acta Neurologica Scandinavica
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